'It can kill, it nearly did': researchers uncover clue to deadly flu in healthy people

Despite being a fit and healthy 32-year-old, Amanda Nix said she is lucky a bout of influenza did not kill her.

"I generally don't get sick very often at all," she said. "I'm still in shock actually, I had no idea it could happen like that to someone like me."

Amanda Nix, who is generally fit and healthy, has just been released from hospital after suffering from a severe case of influenza.Credit:Janie Barrett

Associate Professor Benjamin Tang, an intensive care specialist at Nepean Hospital, has spent the past 10 years researching why some otherwise healthy people develop severe complications when they get influenza.

His latest research, published on Wednesday in Nature Communications, has found a particular immune cell could be to blame.

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With help from scientists, doctors and clinicians from Australia and internationally, the researcher studied blood samples of hundreds of people who presented to hospital emergency departments with influenza.

Professor Tang said they found one type of immune cell, called neutrophils, was "one of the main causes" of patients deteriorating after they get influenza.

Professor Tang's research is 10 years in the making.Credit:Janie Barrett

"They start causing lots of collateral damage, and they do so in huge numbers, and in a way that the body cannot cope and things start to deteriorate," he said.

Ms Nix said she thought she had been recovering from flu symptoms until the body aches and fever returned on Thursday, July 25. Later that night she was woken by heart palpitations. Being a nurse, she realised that could be a sign of infection.

"That's when I knew it was quite serious and I needed to get to hospital," she said.

After arriving at Nepean Hospital by ambulance her condition deteriorated, and a chest X-ray revealed she had developed pneumonia.

"By that time I couldn't breathe on my own," she said.

Influenza in 2019

Nationally, there have been 383 influenza-related deaths. That number may be an underrepresentation due to reporting methods in different parts of the county.

Up to July 30 this year, there have been 184,447 laboratory-confirmed influenza cases across Australia. It's the second-highest recorded number of influenza cases in the last five years.

Source: National Notifiable Diseases Surveillance System

Ms Nix ended up in intensive care for one day. After a few more days of antibiotic and oxygen treatment, she was discharged on Tuesday and is back home in Blaxland, in the Blue Mountains.

"I will definitely be resting for the next couple of weeks," she said.

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Head of Microbiology at Monash University Professor Stephen Turner, who studies host responses to influenza infection, said the findings in Professor Tang's research were "solid".

However, Professor Turner said more research needed to be done to work out whether overreacting neutrophils were causing severe influenza reactions, or whether they were overreacting in response to the severity of the condition.

"This study actually provides now a new lead for people to potentially follow up to see whether or not this is, in fact, a way of developing more specific treatments for severe influenza," he said.

"So if this overactivation of these neutrophils is actually the cause of those complications, you might be able to target those cells or their activation to limit the damage that's being caused."

Professor Tang said that's what the next stage of their research would be looking at, and they were hoping to develop personalised immunotherapy for serious cases.

"We can't go out and say we have found a cure, so this work will lay down the discovery of a cure later on but that's going to be at least another five years away," he said.

Ms Nix said she has been told to take it easy over the next two weeks as she recovers.Credit:Janie Barrett

Professor Tang said his team's discovery was still "pretty pivotal" as there was "no current treatment" for high-risk patients.

"Hopefully an outcome will be that we don't need to see these patients in our intensive care, and to stop patients from deteriorating from what begins as a fairly mild illness," he said.

For now, Ms Nix said people should make sure they take influenza seriously, even if they are fit and healthy.

"You need to look after yourself, it can kill: it nearly did."

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